COMPASS FOR THE BLIND Russian patent published in 1996 - IPC

FIELD: technical facilities allowing the blind to orient themselves by ear, the compass can be useful for sportsmen and people travelling by night. SUBSTANCE: any position of the magnetic needle relative to the scale corresponds to an acoustic vibration of a definite frequency. To this end, the compass scale is made as a ring photodetector consisting of two photodetectors with equal areas. Both photodetectors are cut in a bridge amplifier, and its output is connected to a voltage-to-frequency converter. A sonic energy transducer serves as the output device. Illumination of the photodetectors is effected by visible light through a slot, or by light a radioluminescent source. EFFECT: enhanced efficiency. 3 cl, 3 dwg